Apparatus and method for cooking and dispensing starch

ABSTRACT

An apparatus and method for cooking and dispensing starch to a commercial laundry machine comprising a mixing tank for mixing and storing a starch and water solution which is attached to a means for discharging the starch and water solution to a heat exchanger. The heat exchanger is a shell and tube heat exchanger, either one-phase or two-phase, used for cooking the starch and water solution to form cooked starch. As the starch and water solution is passed through the tube side of the heat exchanger, it is cooked using heat energy from a heating source contained in the shell side of the heat exchanger. The cooked starch is then dispensed through a manifold valve system to one or more commercial laundry machines. After the cooked starch is dispensed, a solenoid valve opened to flush the apparatus with fresh water. A programmable computer receives a request from a commercial laundry machine for a desired starch level, discharges the starch and water solution through the apparatus for cooking, and dispenses the cooked starch to the requesting laundry machine through a series of discharge and manifold valves. The programmable computer controls the solenoid valve for flushing the apparatus with water, the discharging means and a means for recirculating the starch and water solution.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an improved apparatus and method forcooking a starch and water solution to form cooked starch and thendispensing the cooked starch into a commercial laundry machine. Moreparticularly, the present invention relates to an improved commercialstarch cooking apparatus and method wherein the starch and watersolution and a heating source are passed through a heat exchanger forcooking to form cooked starch, which is then delivered to one or morecommercial laundry machines. The present invention cooks and dispensesstarch in single batches or multiple single batches; starch may bedispensed in a continuous stream subject to the heat exchanger size andrate of flow of the constant heating source.

2. Prior Art

In the dry cleaning industry today, there are various starch cookers forcooking a mixture of corn starch and water for the purpose of starchingdress shirts, blue jeans, khaki pants, tablecloths, cotton napkins andother items of clothing. Ideally, the mixture of corn starch and watershould reach a cooked temperature of range of 180 degrees Fahrenheit to205 degrees Fahrenheit, preferably the mixture should be cooked to atemperature range of 190 degrees Fahrenheit to 195 degrees Fahrenheit.If the starch mixture is cooked too hot, the chemical and physicalmakeup of the starch solution continues to change causing, the mixtureto form a glue-like slurry.

Presently, three (3) main methods for cooking starch are used. A firstmethod utilizes an open pan batch method where the starch is hand pouredinto the open pan cooker. This method is extremely dangerous and verylabor intensive. A second method uses an open pan batch to cook thestarch, but the starch is fed into the open pan cooker using a pump andpipe. This method results in high maintenance costs due to starchbuild-up in the pump and pipes, and thus requires continuous, laborintensive cleaning. In addition, this method demands a high level ofattention from the operator. A third method used today is thesteam-injected, closed-batch method utilizing a pump and pipe forfeeding starch into the cooker. This method relies on direct steaminjection from a boiler; however, boiler treatment compounds, along withrust, calcium and other contaminates are also injected with the steaminto the starch. These undesirable contaminants adhere to the clothingitems. Further, this method uses a violent mixture of steam and starchsolution which cannot be accurately controlled resulting in incompletestarch cooking.

Mitchell, et al. (U.S. Pat. No. 5,437,169) discloses a starch cookingdevice that utilizes a tank float device to open and close a watersupply line. The float is immersed in the starch and water solutioncausing starch build-up on the float and pipes thus requiringcontinuous, labor intensive cleaning. Mitchell also discloses usingdirect steam injection to both cook and agitate the starch and watersolution. This may result in lumpy starch, thus causing uneven starchingof garments. Furthermore, as previously mentioned, direct steaminjection may result in contaminants mixing with the starch solutioncausing contamination and discoloration of garments.

Mitchell, et al. (U.S. Pat. No. 5,680,663) discloses a starch cookingdevice that utilizes a tank float device to open and close a watersupply line. The float is immersed in the starch and water solutioncausing starch build-up on the float and pipes, thus requiringcontinuous, labor intensive cleaning. Mitchell also discloses usingdirect steam injection to both cook and agitate the starch and watersolution. This may result in lumpy starch, thus causing uneven starchingof garments. Furthermore, as previously mentioned, direct steaminjection may result in contaminants mixing with the starch solutioncausing, contamination and discoloration of garments.

Mitchell, et al. (U.S. Pat. No. 5,901,584) discloses a starch cookingdevice having a starch cooking valve for direct steam injection. In thispatent, a starch solution is mixed with a direct injection of steam inthe starch cooking valve to form cooked starch. This patent alsoutilizes a hopper and auger assembly to agitate the starch and watersolution. As previously mentioned, the reaction between the starchsolution and a direct injection of steam is violent and may result inthe incomplete cooking, of starch. Further, using an auger to agitatethe starch and water solution may result in the auger tunneling throughthe starch, leaving air pockets or tunnels in the starch and watermixture.

Boling (U.S. Pat. No. 5,964,950) is directed towards a starch cookingdevice having a single vessel or mixing, cooking a starch solution. MSpatent uses a recirculating flow line with a gear pumping arrangement tobreak up lumps in the starch. This patent requires a user to add starchto the vessel for cooking. As discussed above, this hand pour, openbatch method is extremely dangerous for commercial applications, and isalso very labor intensive.

Mitchell, et al. (U.S. Pat. No. 6,507,966) also discloses a starchcooking device that uses a hopper and auger for mixing a starch andwater solution and a steam valve for direct steam injection for cookingthe starch and water mixture. Again, the reaction between the starchsolution and a direct injection of steam is a violent reaction which mayresult in the incomplete cooking of starch. Also, using an auger toagitate the starch and water solution may result in the auger tunnelingthrough the starch, leaving air pockets or tunnels in the starch andwater mixture.

Accordingly, it is desirable to produce a starch cooking device thatcompletely cooks a starch and water solution without the addition of anycontaminants and other impurities.

It is also desirable to form a starch cooking device that utilizes aflushing system to eliminate starch build-up which otherwise requireslabor intensive cleaning.

It is desirable to have a starch cooker that is predominantly automatedusing a programmable computer to control mixing, cooking and flushingprocedures.

It is also desirable for a starch cooker to deliver multiple levels ofstarch to a commercial laundry machine depending on the user's needs.

It is further desirable for a starch cooker to have a closed system inwhich the starch and water solution and the heating source are containedin separate chambers, thus cooking the starch without any possibility ofcontamination during the cooking process.

BRIEF SUMMARY OF THE INVENTION

The present invention relates to an improved apparatus and method forcooking a starch and water solution to form cooked starch and thendispensing the cooked starch to a commercial laundry machine. Thepreferred embodiment of the present invention comprises a mixing tankfor mixing and storing a starch and water solution attached to a meansfor discharging the starch and water solution to a heat exchanger. Theheat exchanger is a shell and tube heat exchanger used for cooking thestarch and water solution to form cooked starch. As the starch and watersolution is passed through the tube side of the heat exchanger, it iscooked using heat energy from a heating source contained in the shellside of the heat exchanger. The cooked starch is then dispensed througha manifold valve system to one or more commercial laundry machines.After the cooked starch is dispensed, an electronic solenoid valve isopened to flush the apparatus with fresh water. A programmable computeris communicably attached to the mixing tank, the recirculating means,the discharging means, the manifold valve system and the solenoid valve.The programmable computer receives a request from as commercial laundrymachine for a desired starch level, discharges the starch and watersolution through the heat exchanger for cooking, and dispenses thecooked starch to the requesting laundry machine through the series ofdischarge and manifold valves.

The present invention cooks and dispenses starch in single batches aswell as multiple single hatches. It may also be used to dispense starchin a continuous stream subject to the heat exchanger size and rate offlow of the constant heating source.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the preferred embodiment of the presentinvention.

FIG. 2 is a perspective, cut-away view of the heat exchanger of thepreferred embodiment.

FIG. 3 is a perspective view of an alternate embodiment of the presentinvention utilizing the heat exchanger, a steam inlet, and atemperature-regulating valve connected to the steam inlet.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The embodiments discussed herein are merely illustrative of specificmanners in which to make and use the invention and are not to beinterpreted as limiting the scope of the instant invention.

While the invention has been described with a certain degree ofparticularity, it is to be noted that many modifications may be made inthe details of the invention's construction and the arrangement of itscomponents without departing from the spirit and scope of thisdisclosure. It is understood that the invention is not limited to theembodiments set forth herein for purposes of exemplification.

FIGS. 1 and 2 show generally the preferred embodiment of the presentinvention designated generally by the numeral 10. Starch cookingapparatus 10 comprises a mixing tank 12 for mixing and storing waterwith dry starch to form a starch and water solution. Mixing tank 12 hasa heating element 14 thermostatically controlled by a temperature probe16 for heating the starch and water solution to an initial temperaturerange of 55 degrees Fahrenheit to 110 degrees Fahrenheit, preferably 79degrees Fahrenheit to 81 degrees Fahrenheit. Those skilled in the artwill appreciate the starch and water solution may also be heated byother heating means, such as using a heating element that is incommunication with a programmable computer 20. The programmable computerwould be programmed to run the heating element to maintain the starchand water solution in the desired temperature range. Located near abottom portion of mixing tank 12 is low liquid level indicator 13. Lowliquid level indicator 13 is communicably attached to an alarm (notshown) which would sound with either an audible or visual warning whenthe tank level is low or when the starch and water solution does notreach the designated parameters. Also located near a bottom portion ofmixing tank 12 is manual drain valve 15 for allowing a user to manuallydrain the mixing tank. Located near a top portion of mixing tank 12 isoverflow pipe 17.

Attached to mixing tank 12 is a means to recirculate the starch andwater solution, shown in FIG. 1 as recirculating pump 18. Recirculatingpump 18 of the preferred embodiment is a high volume recirculating pump,which is communicably attached to programmable computer 20. Programmablecomputer 20 may be preprogrammed to run recirculation pump 18 for shortintervals, such as throughout the day. In the preferred embodiment,recirculating pump 18 requires two (2) connections 21 and 22 locatednear the bottom of mixing tank 12. One of the connections is for intake21 into recirculation pump 18, while the other connection is fordischarge 22 back into mixing tank 12 for mixing and recirculating thestarch and water solution over heating element 14.

Apparatus 10 of the present invention further includes a means fordischarging the starch and water solution from mixing tank 12. In thepreferred embodiment, the means for discharging is a starch deliverypump 23. Like recirculating pump 18, starch delivery pump 23 is a highvolume pump. Starch delivery pump 23 takes suction from a tee connectionin the recirculation pump inlet line 21. This allows starch deliverypump 23 to run simultaneously with recirculating pump 18. Those skilledin the art will appreciate that apparatus 10 may be operated with oneall-purpose, high volume pump, in lieu of recirculating pump 18 andstarch delivery pump 23. Starch delivery pump 23 is communicablyattached to programmable computer 20. Programmable computer 20 receivesa signal from a commercial laundry machine (not shown) specifying theload size and desired amount of starch. The discharging means of thepresent invention delivers the starch and water solution from mixingtank 12 to heat exchanger 30 in order to cook the starch and watersolution to a final temperature.

In the preferred embodiment of the present invention, heat exchanger 30is a shell and tube heat exchanger. Heat exchanger 30 may be either aone-phase or two-phase heat exchanger. Two (2) fluids, the starch andwater solution from mixing tank 12 and a heating source, of differentstarting temperatures, flow through the heat exchanger. Preferably, thestarch and water solution flows through tube side 32 and a heatingsource is located in shell side 34 of heat exchanger 30. Heat istransferred from shell side 34 to the tube side 32, through the tubewalls. In order to transfer heat efficiently, the tube side 32 isoversized to provide for a large heat transfer area and to allow thestarch and water solution to achieve a slow steady temperature rise fromthe initial mixing tank temperature to the final cooked starchtemperature. This low degree temperature approach ensures a stable andaccurate final “cook” temperature. A constant flow of the heating sourcethrough shell side 34 provides heat to slowly and thoroughly cook thestarch and water solution without overheating the cooked starch orintroducing rust, boiler chemicals or other contaminants into the cookedstarch. The temperature of the heating source is preferably constant,above 190 degree Fahrenheit but not above the maximum cooked starchtemperature. The heating source may be hot water, various heating oils,steam condensate, steam or any other fluids, along with a closed looppump system or boiler.

Those skilled in the art will appreciate that the performance of heatexchanger 30 may be affected by the addition of tins or corrugations inone or both directions, which increase surface area and may channelfluid flow or induce turbulence. It is well known in the art of heatexchangers that in order to be able to transfer heat well, the tubematerial should have good thermal conductivity. Because heat istransferred from the hot side to the cold side, there is a temperaturedifference along the tubes. Also, because tube materials tend tothermally expand at varying temperatures, thermal stress on the materialoccurs during the heat exchangers normal operation. The material for theheat exchanger should not react with both the shell and tube side fluidsin order to minimize deterioration, such as rust and corrosion. Thus, itis preferable that the heat exchanger be made of cast iron, steel,stainless steel, copper, aluminum or other strong, thermally-conductive,corrosion-resistant, high quality tube material.

In the preferred embodiment, heat exchanger 30 will have at least onetube side inlet 24 for delivering the starch and water solution to tubeside 32 and at least one tube side outlet 26 for discharging the cookedstarch. Heat exchanger 30 will also have at least heat source one inlet31 and at least one heat source outlet 35 for delivering the heatsource. Preferably, if steam condensate, hot water or hot oil is used asthe heating source, heat source inlet 31 and heat source outlet 35should be located on the top portion of heat exchanger 30. This allowsshell side 34 to be completely filed with a constant flow of the heatingsource. If steam is used as the heating source, heat source inlet 31 andheat source outlet 35 should be located on a bottom portion of heatexchanger 30. As an alternate embodiment, as shown in FIG. 3, if steamis used as the heat source, heat exchanger 30 requires the addition ofsteam outlet 37, steam inlet 38, and a steam temperature-regulatingvalve 39 to insure the steam is at a proper, constant temperature forcooking the starch and water solution.

Once the discharging means, or in the preferred embodiment a starchdelivery pump 23, passes the starch and water solution into tube sideinlet 24 and through tube side 32 of heat exchanger 30 to form cookedstarch, the cooked starch is discharged from tube side outlet 26 anddispensed to one or more commercial laundry machines (not shown). In thepreferred embodiment, a temperature probe 36 is located near the outputof heat exchanger 30 to ensure the cooked starch is cooked to atemperature of range of 180 degrees Fahrenheit to 205 degreesFahrenheit, preferably to 190 degrees Fahrenheit to 195 degreesFahrenheit. When apparatus 10 is used will more than one (1) commerciallaundry machine, the cooked starch is delivered from heat exchanger 30to manifold valve system 40. The control valves of manifold valve system40 are modified ball valves 42 with air piston 44 activation. Ballvalves 42 allow a full throat opening in order to minimize starchblockage. Manifold valve system 40 is communicably attached toprogrammable computer 20. When programmable computer 200 receives arequest from one or more commercial laundry washers, programmablecomputer 20 stacks the request and processes each request with a normalcook and flush cycle. Also connected to manifold valve system 40, is amanual control valve 46 allowing an operator to run a manual starch testfor quality control, thorough cooking and consistency.

In the preferred embodiment of apparatus 10, a flush cycle is alsoperformed to flush the discharging means and tube side 32 of heatexchanger 30 of any remaining starch. A flushing inlet 50 is connectedto a fresh water supply. An electronic solenoid valve 52 is used toregulate the introduction of fresh water. Flushing inlet 50 and solenoidvalve 52 are located between the mixing tank and starch delivery pump 23so that fresh water will flush starch delivery pump 23 and heatexchanger 30. Electronic solenoid valve 52 is communicably attached toprogrammable computer 20. Programmable computer 20 is programmed toflush the system for a pre-determined time depending, upon the distancebetween apparatus 10 and the commercial laundry machine(s). Thepre-determined flush time may also vary on the design of heat exchanger30.

Programmable computer 20 is preferably a programmable logic controllerwhich receives electronic signals from one or more commercial laundrymachines. Programmable computer 20 has multiple pre-programmed stepswhich allows starch delivery pump 23 to TEM for different times, thusdelivering multiple levels of cooked starch. An adjust switch 54 isprovided allowing the operator to select the desired level or starch(light, medium, heavy or extra heavy starch). In addition to adjustswitch 54, push buttons 56 and 58 allow the operator to incrementallychange the desired level of starch, thus allowing the operator to finetune the starch level based on a particular consumer's needs. A teststarch cycle push button 60 is also communicably attached toprogrammable computer 20. Push button 60, in combination with manualcontrol valve 46, to allow the operator to periodically test the starchlevel prior to running a full cycle.

As previously mentioned, programmable computer 20 controls recirculationpump 18 allowing the latter to cycle on and off according to apre-programmed algorithm. Programmable computer 20 also controls starchdelivery pump 23 allowing the latter to deliver multiple levels ofstarch to heat exchanger 30 for cooking. When apparatus 10 is used withmore than one commercial laundry machine, programmable computer 20 isprogrammed to control manifold valve system 40, thus controlling theflow of cooked starch to various commercial laundry machines.Programmable computer 20 also opens and closes solenoid valve 52 toallow fresh water to flush the discharging means, tube side 32 of heatexchanger 30 and all other pipes, valves and fittings associated withthe discharging means. Programmable computer 20 is enclosed in a sealedcontrol box 62 for protection. Control box 62 houses air controlswitches 64 and the motor relay switches 66.

Whereas, the present invention has been described in relation to thedrawings attached hereto, it should be understood that other and furthermodifications, apart from those shown or suggested herein, may be madewithin the spirit and scope of this invention.

1. A method for cooking and dispensing a starch and water solution to atleast one commercial laundry washer, said method comprising the stepsof: (a) filling a mixing tank with water and dry starch to form a starchand water solution; (b) discharging said starch and water solution fromsaid mixing tank into at least one elongate tube of a heat exchanger;(c) delivering a fluid heating source into a shell that substantiallysurrounds said elongate tube of said heat exchanger, (d) indirectlycooking said starch and water solution in said elongate tube by runningsaid fluid heating source over said elongate tube of said heat exchangerto form a cooked starch solution; and (c) dispensing said cooked starchsolution from said elongate tube of said heat exchanger to at least onecommercial laundry machine.
 2. The method of claim 1 further comprisingheating said starch and water solution in said mixing tank to an initialtemperature.
 3. The method of claim 2 further comprising recirculatingsaid starch and water solution for maintaining said initial temperatureand for recirculating and mixing said starch and water solution in saidmixing tank.
 4. The method of claim 1 further comprising flushing saidcooked starch from said elongate tube of said heat exchanger by passingwater through said elongate tube of said heat exchanger after saidcocked starch solution is dispensed into said at least one commerciallaundry machine.
 5. The method of claim 1 further comprising selecting adesired level of starch to be dispensed to said commercial laundrymachine.
 6. The method of claim 1 wherein said heat exchanger furthercomprises: said shell containing said fluid heating source for providingheat energy to cook said starch and water solution to a finaltemperature; said elongate tube for cooking said starch and watersolution to form said cooked starch solution; at least one inlet fordelivering said fluid heating source into said shell; at least one inletfor delivering said starch and water solution into said elongate tube;at least one outlet for dispensing said fluid heating source; and atleast one outlet for dispensing said cooked starch solution to said atleast one commercial laundry machine.
 7. A method for cooking anddispensing a starch and water solution to at least one commerciallaundry washer, said method comprising the steps of: (a) filling amixing tank with water and dry starch to form a starch and watersolution; (b) passing said starch and water solution from said mixingtank through a heat exchanger for cooking said starch and water solutionto form a cooked starch solution, wherein said heat exchanger comprises:a tube side containing said starch and water solution; a shell sidecontaining a heating source for cooking said starch and water solutionto form a cooked starch solution; at least one starch and water solutioninlet for delivering said starch and water solution into said tube side;at least one heating source inlet for delivering said heating sourceinto said shell side; at least one cooked starch outlet for dispensingsaid cooked starch solution from said tube side to said at least onecommercial laundry machine; at least one heating source outlet fordispensing said heating source from said shell side; and (c) dispensingsaid cooked starch solution from said heat exchanger to at least onecommercial laundry machine.
 8. The method of claim 7 further comprisingthe steps of: heating said starch and water solution in said mixing tankto an initial temperature; recirculating said starch and water solutionin said mixing tank for a first pre-determined time to prevent saidstarch and water solution from settling in said mixing tank and formaintaining said initial temperature of said starch and water solution;passing said starch and water solution through said heat exchanger forcooking said starch and water solution to a final temperature to formsaid cooked starch solution; passing said starch and water solutionthrough said heat exchanger for a second pre-determined time based on adesired amount of said cooked starch solution to be dispensed to said atleast one commercial laundry machine; and flushing said heat exchangerfor a third pre-determined time to ensure all of said cooked starchsolution is delivered to said at least one commercial laundry machine.9. The method of claim 7 further comprising the step of selecting adesired level of starch to be dispensed to said commercial laundrymachine.
 10. The method of claim 1 further comprising the steps of: (a)tilling a mixing tank with water and dry starch; (b) mixing said waterand dry starch in said mixing tank to form a starch and water solution;(c) heating said starch and water solution in said mixing tank to aninitial temperature using at least one thermostatically controlledheating element in said mixing tank; (d) discharging said starch andwater solution out a drain valve of said mixing tank and into at leastone tube inlet of said elongate tube of a heat exchanger; (e) deliveringsaid heating fluid through at least one shell inlet into a shell of saidheat exchanger; (f) indirectly cooking said starch and water solution toa final temperature in said elongate tube by running said heating fluidover said elongate tube of said heat exchanger to form a cooked starchsolution; (g) dispensing said cooked starch solution from at least onetube outlet of said elongate tube of said heat exchanger to at least onecommercial laundry machine; and (h) discharging said heating fluid fromat least one shell outlet of said shell of said heat exchanger.
 11. Themethod of claim 10 wherein said step (c) of heating said starch andwater solution further comprises the steps of: (a) maintaining saidinitial temperature of said starch and water solution in said mixingtank; and (b) recirculating said starch and water solution in saidmixing tank.